Alternative Technology Assn Forums

1. 

   Taras
   Member

   I have bought a 6 yr old house a month ago and it has 315 lts solar hot water system with electric boost (not sure when it was installed-no papers provided). I had electricity bill worth 300 $ for 26 days. The water in my taps comes very hot even when turned to extreme cold side specially in day time.
   I turned off the electric boost to my solar hot water and now in the day time the water is hot but by next morning for early shower it is cold (without electric boost).

   I have heard that people have solar hot water even with 24 hrs of couldy sky or rain and no electric or gas boost at all. Is it true.

   Could there be anything wrong with my system?
   Where should I start looking from?

   Posted Wednesday 16 Jan 2013 @ 12:23:39 pm from IP #
2. 

   Fab
   Member

   Seems you have a storage insulation problem Taras

   Our solar water heater is a 325 litre and stays hot for at least two days of cloudy or rain conditions.
   There is only two of us and we use hot water for showers only.

   Electric boost is noticable if I turn it on and I can tell if I forgot to turn it off.

   I would check the plumbing and insulation to the shower heads also.

   Posted Saturday 19 Jan 2013 @ 8:50:59 pm from IP #
3. 

   Morbo
   Member

   At this time of year 250L gets 2 people through 3 days when its fully charged to 70 down to 45. At present am using hot water in my washing machine, just to get rid of it, otherwise the thing switches off at 70deg.
   Check the controller, you could flick through temperatures at panel outlet, tank outlet, tank inlet. Does it do anythink at all. Is the pump running. Sunny today. You could hear a relais clicking when the pump goes on/off. Then there is a test button just to switch the pump on, it should be vibrating then just so so.
   Whats extremly hot, scalding valve should reduce it to 55 deg.
   Tank insululation could be dodgy, too, but ours is a stainless tank foamed into a plastic shell, plumber could not muck up this one.

   Is it electric instantaneous or electric storage? Maybe the controller tries to cool it down at the same time because its at 70 deg in the morning and plenty of sun? Or it bleeds the tank at daytime because its overheating? No idea to what degree a storage tank is heated up, got gas instantaneous, solar gas storage does not make sense.

   Posted Saturday 19 Jan 2013 @ 9:10:43 pm from IP #
4. 

   Fab
   Member

   The green light flashes during the day when my pump is working but stays on at night when it is not.
   Another possibility it may be continually pumping and cooling the water in your storage tank at night.
   I was told by my installer the difference in temperature between thermostats on the roof panels and the inlet to the tank determines if the pump should commence.
   Listened to it start working and it's like a steam engine slow pump and then when the roof panels heat up pumps faster.
   Yes I know, I have a lot of time on my hands.

   Posted Monday 21 Jan 2013 @ 5:42:53 am from IP #
5. 

   Morbo
   Member

   7 deg difference they say. There is a small LED when pump is on, single speed suppose. Danfoss pump on solastat controller, maybe different on other systems.

   Posted Monday 21 Jan 2013 @ 10:30:31 am from IP #
6. 

   Greg C
   Member

   We need some more details. Is it a pumped system, i.e. tank on the ground and collectors on the roof. If that, I would say your pump is running non stop and so is radiating all the heat you collect in the day to space as it runs the water through the collectors at night.

   What sort of collectors etc etc.

   Just to prove it should work, our system is tank on ground with a pump and collectors on the roof. If you have a system like this you have to have a one way valve in the circuit to prevent reverse thermosyphon. Ours works a treat and has done since 1990.

   Where is the booster element and what tariff is it supplied by. Ours is in the top hole in the tank and on continuous tariff. I would recommend that.

   Posted Monday 21 Jan 2013 @ 11:25:24 am from IP #

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